1. Field
The following description relates to a CMOS image sensor, and a CMOS image sensor capable of expanding a dynamic range, and a driving method thereof.
2. Description of the Related Art
Recently, equipments, such as a digital camera, a camera phone, a machine vision, a surveillance camera, etc., including a high-resolution camera, have been widely popularized. Such a high-resolution camera utilizes a Charged Coupled Device (CCD) or a CMOS image sensor as an image pickup device.
Since a conventional CMOS image sensor has a dynamic range of about 50-60 dB, there are limitations in generating images having a wide illumination range. For this reason, there occurs a case where a value of a bright part on a screen is saturated and the bright part appears white or a dark part on the screen is invisible. Also, due to miniaturization of equipments such as a digital camera or a camera phone, pixel size reduction and low power driving of an image sensor are required, but a sufficient dynamic range cannot be ensured through low voltage driving for satisfying such requirements.